Patent application title: Cladding part for component

Abstract:

The invention relates to a cladding part for components. The cladding part
has at least two areas with different vibration damping properties. The
different areas make it possible in a simple manner to meet partly
conflicting requirements for cladding parts of the components in an
optimum manner. The components include medical examination devices.

Claims:

1-12. (canceled)

13. A cladding part for a component, comprising:a first area having a
first vibration-damping property; anda second area having a second
vibration-damping property that is different to the first
vibration-damping property.

14. The cladding part as claimed in claim 13, wherein the first area and
the second area of the cladding part are arranged in accordance with
vibration excitation properties of respective adjacent points of the
component.

15. The cladding part as claimed in claim 13, wherein the first area of
the cladding part comprises a material having a high density for
reinforcement.

16. The cladding part as claimed in claim 15, wherein the first area of
the cladding part comprises fiber-reinforced plastic.

17. The cladding part as claimed in claim 13, wherein the second area of
the cladding part comprises a material having a lower density than a
material in the first area.

18. The cladding part as claimed in claim 13, wherein the second area of
the cladding part comprises a sound-deadening material for vibration
decoupling.

19. The cladding part as claimed in claim 18, wherein an outer side of the
cladding part is vibration decoupled from an inner side of the cladding
part.

20. The cladding part as claimed in claim 18, wherein the sound-deadening
material is a sound-deadening foam.

21. The cladding part as claimed in claim 20, wherein the sound-deadening
foam is a linear polyetherimide hard foam material.

22. The cladding part as claimed in claim 13, further comprising a third
area comprising a low-cost or a drapable material having a lower density
than a material in the first area.

23. The cladding part as claimed in claim 13, wherein an outer side or an
inner side of the cladding part comprises fiber-reinforced plastic for
reinforcement.

24. The cladding part as claimed in claim 13, wherein the second area is a
sandwich form comprising a material having a higher density and a
material having a lower density.

25. The cladding part as claimed in claim 13, wherein the second area has
a lower curvature than the first area.

26. The cladding part as claimed in claim 13, wherein the component
comprises a medical examination device.

[0003]Cladding of components, especially medical examination devices such
as computer tomography devices or magnetic resonance devices for example,
or also for radiation therapy devices, in addition to improving the
external appearance of said devices, also frequently serves to attenuate
sound externally which is produced by the component during operation and
which, without sound deadening or attenuation, can be perceived by a
person located in the vicinity of the component as unpleasant noise. In a
magnetic resonance device for example noise typically arises from
interaction between a main field magnet and the gradient coils used for
local encoding. With computer tomography devices and radiation therapy
devices, noise can be generated for example during rotation of parts of
the devices during an examination or treatment.

[0004]The noise arising will be transmitted directly or indirectly e.g.
via the air surrounding the component, to cladding of the component,
which also causes said cladding to vibrate, and thus passes on the noise
and/or in its turn creates further noise.

[0005]Known cladding of just such medical examination devices is generally
simply made from fiber-reinforced plastics, which thus possess a high
mass and are therefore heavy, inherently rigid and not easy to handle.
Although such cladding provides an attenuating mass to counter
vibrations, it still directs noise unimpeded into the cladding.

[0006]Furthermore cladding is known which is also made of pure
fiber-reinforced plastic and is additionally provided on the side facing
the component with a sound-deadening layer made of foam. Thermoplastic
cladding parts also exist which are manufactured using the single-sheet
or twin-sheet method and sections of which are also provided with
sound-deadening foam. Although this improves its vibration-damping
properties, mass and thereby weight of the cladding continue to be
impractical.

SUMMARY OF THE INVENTION

[0007]One object of the invention is thus to specify a cladding part for
optimized cladding.

[0008]The object is achieved by a cladding part in accordance with the
claims.

[0009]In such cases the cladding part comprises at least two areas with
different vibration damping properties.

[0010]The different areas make it possible in a simple manner to fulfill
in the optimum manner the sometimes conflicting requirements on cladding
parts of components, especially medical examination devices.

[0011]Such requirements are for example that cladding parts of components
should on the one hand, for better sound deadening and stability, be
constructed to be as heavy and massive as possible, but on the other
hand, for reasons of handling, especially for service measures, should be
as light as possible.

[0012]Furthermore it is desirable from an economic standpoint for cladding
parts to be constructed as simply as possible and thus be simple to
manufacture. A suppression of body sound transmission within the cladding
parts is also desirable. Inventive cladding parts will also easily meet
these requirements and even make it possible in this case both to fulfill
locally differing requirements e.g. regarding suppression of sound
propagation or transfer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]Further advantages and details of the present invention emerge from
the exemplary embodiments described below, as well as with reference to
the drawings. The outlined examples do not represent any restriction of
the invention. The figures are as follows:

[0014]FIG. 1 a schematic diagram of a front view of a rear or front
cladding part of a magnetic resonance device as an example of an
inventive cladding part and

[0015]FIG. 2 the rear or front cladding part from FIG. 1 in a longitudinal
cross section.

DETAILED DESCRIPTION OF THE INVENTION

[0016]Without this being intended to represent any restriction, FIGS. 1
and 2 show, in a front view and in a longitudinal cross section
respectively, a schematic diagram of an inventive cladding part 1 of a
component 10 using front or rear cladding 1 of a magnetic resonance
device 10 as an example.

[0017]The magnetic resonance device 10 especially comprises a cylindrical
magnet 9 for creating a main magnetic field in an examination volume U of
the magnetic resonance device 10. Furthermore the magnetic resonance
device 10 comprises a gradient coil unit 11 for creating gradient fields
in the examination volume U. During an examination the main magnetic
field is overlaid for location encoding of the measurement data with
rapidly switched magnetic gradient fields. In this case forces act
between gradient coil unit 11 and magnet 9 which excite the gradient coil
unit 11 and the external jacket of the magnet 9 into vibrations. Further
elements of the magnetic resonance device 10 such as control units and
the like for example are known and are not shown in the figure for
reasons of clarity.

[0018]The component 10 to be clad, the magnetic resonance device 10 in
this case, thus at least in some places, namely at least by the gradient
coil unit 11, excites its environment into vibrations. The gradient coil
unit 11 is protected from the examination volume U by inner cladding 13
for example.

[0019]In the example shown the cladding part 1 has three areas with
different vibration damping characteristics 3, 5, 7. These are arranged
in accordance with vibration excitation characteristics of the respective
adjacent points of the component.

[0020]Through the vibrations of the gradient coil unit 11 sound is mostly
emitted at the height of the gradient coil unit 11 viewed radially from
the longitudinal axis of the magnetic resonance device 10. Viewed in a
radial outwards direction, the intensity of this sound emission and
thereby the excitation of vibrations in the environment become weaker. In
a central area of the so-called "end spinnings" (=front face sides) of
the magnets 9 the radiation is less high compared to the directly
opposite the gradient coil unit 11 and is lowest in the outermost area.

[0021]Accordingly the areas 3, 5, 7 are arranged so that a first area 3 of
the cladding part 1, which comprises materials for stiffening which have
a high density, is located at the height of the gradient coil unit 11,
i.e. in the active area of a high vibration excitation of the component
10. The high density of the first area 3 imparts to the cladding part 1
at this location the necessary mass to be able to cater for the main
sound emission. Advantageously the first area 3 comprises
fiber-reinforced plastic, especially glass fiber-reinforced plastic, e.g.
polyester or epoxy resin and glass fibers.

[0022]The further areas 5, 7, which are arranged outside the main sound
emission and are primarily excited into vibrations by air sound which
exits from the gradient coil unit 11 comprise materials which have a
lower density than materials in the first area 3.

[0023]In such cases especially the second area 5, which in an active area
is assigned average vibration excitation by the component 10, comprises
damping material with a vibration damping effect. On the one hand this
has the advantage of the cladding part 1 being reduced in weight by the
lower density of the materials and on the other hand the vibrations to
which the cladding part 1 is excited by the sound transmitted by the
gradient coil unit 11 are damped.

[0024]In this case it is advantageous for the damping material in the core
of the area 5 of the cladding part 1 to be arranged so that especially an
outer side 6 of the cladding part 1 is vibration-decoupled from an inner
side 4 of the cladding part 1. In particular sound-deadening materials
made from soft structures, for example damping foams, such as linear
polyetherimide hard foam plastic, are suitable as sound-deadening
materials.

[0025]In addition this exemplary embodiment shows a third area 7 of the
cladding part 1 which also comprises materials of lower density. This
third area 7 is arranged in the effective area of lower vibration
excitation of the component 10 and primarily serves for further reduction
of the total weight of the cladding part 1. The density of the material
used here in the outer area 7 can even be less than that of the material
used in the active area of medium vibration excitations, since here the
vibration excitations by the component 10 are again smaller. Thus in this
area 7 extremely cost-effective cell material can be used for reducing
density. For example fleece, such as pressure-stable polyester fleece for
example, is especially suitable in this case--because of its easy
drapability for example.

[0026]The inventive cladding part 1 is thus optimized by arrangement of
the different areas corresponding to the different vibration excitations
by component 10 in respect of its vibration-damping characteristics and
thereby of its sound-deadening characteristics. In addition the weight of
the cladding part 1 is reduced 1 by using materials of lower density
compared to conventional cladding parts, which facilitates handling of
the cladding part 1. The costs for such a cladding part 1 can also be
kept especially low by using low-cost materials of low density in areas 5
and 7.

[0027]This type of cladding part 1 can also be manufactured simply and
cost-effectively. One example for a possible method of manufacturing such
a cladding part 1 would for example be by means of a molded part for the
cladding part 1, in which a 5-6 mm thick layer of glass fibers were
arranged for the inner area 3 for example. In the adjacent central area 5
for example first of all a thin layer (appr. 14 mm) of glass fibers for
stabilizing the outer side 6 of the cladding part 1, then a layer of
damping material for vibration decoupling and weight reduction, e.g.
sound-deadening foam of a thickness of appr. 3-4 mm, and another thin
layer (appr. 14 mm) of glass fibers for stabilizing the inner side 4 of
the cladding part 1 are arranged in a sandwich configuration. In the
outer area 7 once again adjoining the central area 5, in a similar manner
a appr. 3-4 mm thick layer of polyester fleece or another cost-effective
and easily shapable material of lower density, which serves here only as
a filler for weight reduction, is arranged between two thin layers (each
appr. 14 mm) of glass fibers in the form of a sandwich. Now the cladding
part 1 can be molded in the mold part, e.g. by means of an injection
method with resin or another suitable plastic. In such cases the glass
fibers serve as a flow aid inter alia. So that it is also made easier for
the resin to flow around the sound-deadening foam, and in order to
prevent the formation of sound bridges in the central area 5 (which would
be caused especially by cavities within the sound-deadening foam for
example), the sound-deadening foam can in each case be provided on its
side facing the inner and outer side respectively with channels running
across each other for example.

[0028]Such channeling of the sound deadening foam simultaneously
advantageously increases the ability to shape the sound deadening-foam
component, so that there is no need to shape the sound deadening foam
before it is inserted into the mold. This applies particularly in
connection with a material thickness of the sound deadening foam of only
a few millimeters, such as in the example given.

[0029]In the example of a rear or front cladding part as cladding part 1
in particular the low curvature in the second area 5 facilitates the
sandwich-type construction of the second area 5 with a core made of
sound-deadening material.

[0030]Thus a cladding part 1 is produced which achieves a certain degree
of stability by the through-layers of glass fiber-reinforced plastic on
the inner and outer side 4, 6 of the cladding part 1 and simultaneously
has the advantages already given above.

[0031]The said measurements, dimensions and configurations relate to the
example of front and rear cladding 1 of a magnetic resonance device 10.
For the person skilled in the art other cladding parts have other
dimensions and arrangements of the different areas 3, 5, 7 easily
recognizable depending on requirements.

[0032]In order to also suppress propagation of airborne sound between the
component 10 and the cladding part 1, further barriers 15, e.g. made from
sound-deadening foam or other noise-suppression materials, can be
arranged at a suitable position between the component 10 and the cladding
part 1. This relates especially to airborne sound at the loudest point,
i.e. in the area of the gradient coil 11, which migrates outwards over
the endspinnings (end faces of the component 10).